Wizards coming of age

[alhewison]

No: HPFGUIDX 37661

I've just been idling away a bit of time wondering why wizards come 
of age at 17 - not 18.

JKR mirrors the British Muggle world in so many ways - OWLs - 
O'Levels, NEWTs - A'Levels, Apparition Test aged 17 - Driving Test 
aged 17. It therefore seems significant that wizards come of age a 
year earlier than Muggles.

I wonder whether Harry will lose the special protection he gets from 
the Dursleys when he reaches 17. Perhaps they will chuck him out (if 
they haven't already!), even if in their Muggle World they should 
remain Legal Guardians until Harry is 18. I also wonder if Harry will 
finally be told his "back story" when he becomes a fully fledged 
wizard - I suppose that's what you become when you come of age in the 
WW, if you become a "man" in the Muggle one? Also, once wizards reach 
17, are they then allowed to use magic, even if they still go to 
Hogwarts?

Perhaps all the above is wrong, but I am sure that Harry's 17th 
Birthday will be important.

Ali